Archive for the ‘Radiators’ Category

We live in Massachusetts in a house built in 1927 that has an aging oil-fired steam boiler and single-pipe radiators. It’s getting more difficult to find replacement radiators and folks who know how to maintain these systems. We hear we’re going to be dinosaurs soon.

What kind of heating system(s) should we investigate as a potential replacement for our steam heating system? We’d like to minimize the cost (we know it will be expensive, whatever we do). By the way, we’re in a rural area that has no natural gas service, although it’s possible to get propane deliveries (as well as oil, of course).

Ours is probably not the ideal property for solar (and we don’t live in the ideal part of the country, either). Some folks in town have tried getting permission for wind turbines, but there are significant restrictions (our property doesn’t meet the requirements). One of our neighbors has installed a geothermal forced hot air system that runs off a standing column well (consumes electricity but no fossil fuels); it seems to be working well for them, but they already had a forced hot air system and even so it was a huge initial capital outlay.

Thanks for your advice!

Melissa Webster

Melissa:

I am sure you already know, the problem is not what kind of heating system you install, its that old construction with limited or no wall insulation and minimum ceiling/roof insulation.

Any money you spend now to add more insulation and re-caulk to reduce air infiltration will make any system you install much more cost effective. If you like the old steam radiators, there are ways to convert these over to hot water heating by adding new supply and return piping, or you could just replace them with new hot water baseboard radiation. You will see a major savings regardless of fuel just by switching out that old steam boiler operating at about 60% efficiency, with a new high efficiency hot water boiler available with efficiencies up to 94%.

Unless you do a major renovation to greatly reduce the heat loss of any old home, I think you will find it almost impossible to heat using a heat pump, even geo-thermal. If this is the case and propane or natural gas is not an option, stay with the oil, but replace all the steam piping with a zoned copper supply and return pumped hot water system.

Finally, you did not say, but I assume you also use a wood stove on really cold days. If not, that would be my first purchase.

I’m remodeling my basement and the over head cast iron heat pipes that supply heat to the radiators are positioned low and a bit from the walls. A plumber suggested replacing them with copper pipe and lifting them closer to the ceiling and walls where they can be enclosed in a soffit. My question is will a smaller copper pipe reduce the efficiency of heat supplied by the radiators throughout the house? The current cast iron pipes are about 3.5 inches wide.

Thank you,

John

John:

Many of these older heating systems used very large size cast iron pipe because they did not have any hot water pumps to circulate the hot water and they operated at very low or no pressure. The large piping provided a kind of thermo-siphon effect which allowed hot water to rise and cold water to return without a pump. In this case, the large pipe size was not due to a high water flow rate. If your new system now has a circulating pump, you will not need large piping since the higher flow rates and system pressure to remove air can transfer much more heat per hour.

A 1-1/2″ copper pipe has a flow rate of over 20 gallons of hot water per minute with a nominal pressure drop, which is probably more than your pump can pump. A 1″ copper pipe can flow 9 gallons per minute. Except for the main headers, I would bet most of your piping run-outs to radiators are only 3/4″, but this size pipe can still flow 5 GPM in each leg which will add up to the main header flow rate. Remember, a smaller pipe costs less to insulate.